/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

interface nsIDOMWindow;
interface nsIDOMNode;

/**
 * nsISessionStore keeps track of the current browsing state - i.e.
 * tab history, cookies, scroll state, form data, POSTDATA and window features
 * - and allows to restore everything into one browser window.
 *
 * The nsISessionStore API operates mostly on browser windows and the tabbrowser
 * tabs contained in them:
 *
 * * "Browser windows" are those DOM windows having loaded
 * chrome://browser/content/browser.xul . From overlays you can just pass the
 * global |window| object to the API, though (or |top| from a sidebar).
 * From elsewhere you can get browser windows through the nsIWindowMediator
 * by looking for "navigator:browser" windows.
 *
 * * "Tabbrowser tabs" are all the child nodes of a browser window's
 * |gBrowser.tabContainer| such as e.g. |gBrowser.selectedTab|.
 */

[scriptable, uuid(43ec216b-f002-4424-bfc5-fc555c87dbc4)]
interface nsISessionStore : nsISupports
{
  /**
   * Initialize the service
   */
  jsval init(in nsIDOMWindow aWindow);

  /**
   * Is it possible to restore the previous session. Will always be false when
   * in Private Browsing mode.
   */
  attribute boolean canRestoreLastSession;

  /**
   * Restore the previous session if possible. This will not overwrite the
   * current session. Instead the previous session will be merged into the
   * current session. Current windows will be reused if they were windows that
   * pinned tabs were previously restored into. New windows will be opened as
   * needed.
   *
   * Note: This will throw if there is no previous state to restore. Check with
   * canRestoreLastSession first to avoid thrown errors.
   */
  void restoreLastSession();

  /**
   * Get the current browsing state.
   * @returns a JSON string representing the session state.
   */
  AString getBrowserState();

  /**
   * Set the browsing state.
   * This will immediately restore the state of the whole application to the state
   * passed in, *replacing* the current session.
   *
   * @param aState is a JSON string representing the session state.
   */
  void setBrowserState(in AString aState);

  /**
   * @param aWindow is the browser window whose state is to be returned.
   *
   * @returns a JSON string representing a session state with only one window.
   */
  AString getWindowState(in nsIDOMWindow aWindow);

  /**
   * @param aWindow    is the browser window whose state is to be set.
   * @param aState     is a JSON string representing a session state.
   * @param aOverwrite boolean overwrite existing tabs
   */
  void setWindowState(in nsIDOMWindow aWindow, in AString aState, in boolean aOverwrite);

  /**
   * @param aTab is the tabbrowser tab whose state is to be returned.
   *
   * @returns a JSON string representing the state of the tab
   *         (note: doesn't contain cookies - if you need them, use getWindowState instead).
   */
  AString getTabState(in nsIDOMNode aTab);

  /**
   * @param aTab   is the tabbrowser tab whose state is to be set.
   * @param aState is a JSON string representing a session state.
   */
  void setTabState(in nsIDOMNode aTab, in AString aState);

  /**
   * Duplicates a given tab as thoroughly as possible.
   *
   * @param aWindow is the browser window into which the tab will be duplicated.
   * @param aTab    is the tabbrowser tab to duplicate (can be from a different window).
   * @param aDelta  is the offset to the history entry to load in the duplicated tab.
   * @returns a reference to the newly created tab.
   */
  nsIDOMNode duplicateTab(in nsIDOMWindow aWindow, in nsIDOMNode aTab,
                          [optional] in long aDelta);

  /**
   * Get the number of restore-able tabs for a browser window
   */
  unsigned long getClosedTabCount(in nsIDOMWindow aWindow);

  /**
   * Get closed tab data
   *
   * @param aWindow is the browser window for which to get closed tab data
   * @returns a JSON string representing the list of closed tabs.
   */
  AString getClosedTabData(in nsIDOMWindow aWindow);

  /**
   * @param aWindow is the browser window to reopen a closed tab in.
   * @param aIndex  is the index of the tab to be restored (FIFO ordered).
   * @returns a reference to the reopened tab.
   */
  nsIDOMNode undoCloseTab(in nsIDOMWindow aWindow, in unsigned long aIndex);

  /**
   * @param aWindow is the browser window associated with the closed tab.
   * @param aIndex  is the index of the closed tab to be removed (FIFO ordered).
   */
  nsIDOMNode forgetClosedTab(in nsIDOMWindow aWindow, in unsigned long aIndex);

  /**
   * Get the number of restore-able windows
   */
  unsigned long getClosedWindowCount();

  /**
   * Get closed windows data
   *
   * @returns a JSON string representing the list of closed windows.
   */
  AString getClosedWindowData();

  /**
   * @param aIndex is the index of the windows to be restored (FIFO ordered).
   * @returns the nsIDOMWindow object of the reopened window
   */
  nsIDOMWindow undoCloseWindow(in unsigned long aIndex);

  /**
   * @param aIndex  is the index of the closed window to be removed (FIFO ordered).
   *
   * @throws NS_ERROR_INVALID_ARG
   *   when aIndex does not map to a closed window
   */
  nsIDOMNode forgetClosedWindow(in unsigned long aIndex);

  /**
   * @param aWindow is the window to get the value for.
   * @param aKey    is the value's name.
   *
   * @returns A string value or an empty string if none is set.
   */
  AString getWindowValue(in nsIDOMWindow aWindow, in AString aKey);

  /**
   * @param aWindow      is the browser window to set the value for.
   * @param aKey         is the value's name.
   * @param aStringValue is the value itself (use JSON.stringify/parse before setting JS objects).
   */
  void setWindowValue(in nsIDOMWindow aWindow, in AString aKey, in AString aStringValue);

  /**
   * @param aWindow is the browser window to get the value for.
   * @param aKey    is the value's name.
   */
  void deleteWindowValue(in nsIDOMWindow aWindow, in AString aKey);

  /**
   * @param aTab is the tabbrowser tab to get the value for.
   * @param aKey is the value's name.
   *
   * @returns A string value or an empty string if none is set.
   */
  AString getTabValue(in nsIDOMNode aTab, in AString aKey);

  /**
   * @param aTab         is the tabbrowser tab to set the value for.
   * @param aKey         is the value's name.
   * @param aStringValue is the value itself (use JSON.stringify/parse before setting JS objects).
   */
  void setTabValue(in nsIDOMNode aTab, in AString aKey, in AString aStringValue);

  /**
   * @param aTab is the tabbrowser tab to get the value for.
   * @param aKey is the value's name.
   */
  void deleteTabValue(in nsIDOMNode aTab, in AString aKey);

  /**
   * @param aName is the name of the attribute to save/restore for all tabbrowser tabs.
   */
  void persistTabAttribute(in AString aName);
};
